Now, what happened after they ate of the tree?
First, they did not surely die!
They died spiritually immediately and started to die (age) also immediately which is why Adam died some 930 years later.
Second, their eyes were opened, as the serpent said.
Their eyes were opened, but not in the way they thought. They felt shame and embarrassment and gained their selfish nature.
Third, they became like God, knowing good and evil, like the serpent said!
They didn't become like God at all -unless you believe yourself to be God?
Genesis 3:22 Then the Lord God said, “Behold, the man has become like one of Us, knowing good and evil; and now, he might stretch out his hand, and take also from the tree of life, and eat, and live forever”— 23 therefore the Lord God sent him out from the garden of Eden, to cultivate the ground from which he was taken.
Mankind gained an inner knowledge of good and evil. Normal people associate certain words with good and evil. If I say murder you should say evil, if I say love you should say good. Unfortunately, that is where it ends and not all people know the difference between good and evil, some find evil fun and think love is weakness. However, because we do have this basic knowledge inside of us and we are responsible for how we use it.
According to the Bible, there was a risk that a man would live forever AFTER eating from the tree, from which God said they would DIE if they eat it's fruit. Think about it. In other words, why is there a fear that people might live forever after they eat of the tree of knowledge? Because the tree of LIFE gives life - thats why!
Before Adam sinned they didn't have to eat from the tree of life to live forever. Notice there is no verse where God instructs Adam to eat the fruit daily before he sinned, if it was important for Adam to do so it would have been mentioned, it's not because we know sin brought in death. Meaning before sin there was no death.
Romans 5:12
Therefore, just as sin entered the world through one man, and death through sin, and in this way death came to all people, because all sinned--
So why was the tree there? Well for one it symbolized God as being the source of life and blessings, plus being alongside the other tree is showed man's choice. Satan's side or God's side. Once they were sent out of the garden it also represented how man had no way back to God by his own strength.
35 Then Jesus declared, “I am the bread of life. Whoever comes to me will never go hungry, and whoever believes in me will never be thirsty.
God is life.
People died, according to the Bible, not because they ate of the tree of knowledge, but because God sent them out of Eden, preventing them from eating of the tree of life!
People die because Adam sinned -his sin caused death.
This is why perfect blood was needed to remove sin and restore us spiritually. Jesus is called the last Adam because when he was tempted he didn't sin and when he died he died without sinning. Dying without sin meant he could take our sin.
1 Corinthians 15:45
So it is written: "The first man Adam became a living being"; the last Adam, a life-giving spirit.
Ephesians 1:7 In him we have redemption through his blood, the forgiveness of sins, in accordance with the riches of God’s grace.
God didn't use death and blood as a redemption tool simply because he thought it was a good idea, it had to be death and blood because historically sin is tied to death and blood. Even the garments God made for Adam and Eve were a picture of Christ covering our sin with his blood. The Bible is full of these prophesy and fulfilment pictures.